Filter mask



FIG. 1 is a front view of a filter mask showing my new design;

FIG. 2 is a rear view of the filter mask of FIG. 1;

FIG. 3 is a left side view of the filter mask of FIG. 1;

FIG. 4 is a right side view of the filter mask of FIG. 1;

FIG. 5 is a bottom plan view of the filter mask of FIG. 1;

FIG. 6 is a top plan view of the filter mask of FIG. 1; and,

FIG. 7 is a bottom perspective view of the filter mask of FIG. 1.

The broken lines shown in the drawings illustrate portions of the filter mask and form no part of the claimed design. 

CLAIM I claim the ornamental design for a filter mask, as shown and described. 